How to fix a crack in drywall

Drywall cracks are simple to repair with a few simple tools and supplies and require little skill.

Photo Credit: Suzanne Carter-Jackson

By Cindy Kennedy
Eventually, somewhere within your home, a crack is going to appear on a wall. House settling is probably the main culprit, but walls can also receive abuse from furniture moves and from people.

First, we should understand that our walls are made of drywall. Other names for drywall are gypsum board, plasterboard, and wallboard. Drywall is comprised of two heavy pieces of paper that sandwich gypsum plaster in between. Drywall typically comes in 4-foot widths. Eight-foot and twelve-foot heights are most readily available. Thickness varies with ½-inch being the most common. Types of drywall include greenboard, which is designed specifically for use in bathrooms, and backerboard, which is very hardy and can even be used on floors.

The boards connect at the studs with nails. Then a tape and bedding procedure covers the seams and fasteners. Tape straddles the seam followed by layers of joint compound. Each compound layer dries and is then sanded smooth. Texture or stucco and paint are then applied. You can also place wallpaper directly over drywall.

When the sheetrock moves, cracks begin to form. Nails can pop up and tape may loosen, which will expose cracking or separation at the seams. If a house is undergoing major settling, cracks can occur elsewhere as well: angling from interior doorways or at ceiling seams. Cracks can also occur because of application defects; for instance, the compound did not dry thoroughly before painting.

The size of the crack and its location will determine which procedure to use.

If you are dealing with an angling crack that is 1/8 inch or less in size, then try these steps. Note that this method is for hairline cracks only. If the house continues to settle, chances are that the crack will reappear. This method is a quick, temporary fix.

Purchase joint compound, fine grit sandpaper, and a putty knife. Joint compound is available in small quantities at your local home improvement or discount store. Some types are fast-drying and some are labeled flexible, which is a good choice if you expect continued movement in the walls. For home users, premixed is best, although powder forms that mix with water are available. Use water resistant compound in bathrooms or high humidity areas.

Load the putty knife with compound. Sweep the knife in a back and forth angled motion to work the putty into the crack. Keep forcing putty in so it will fill as far into the crack as possible. Allow plenty of time for drying as this step is critical to the final appearance of the wall. Always follow the manufacturer's instructions for drying time. Sand the area smooth and until you can detect no ridges or bumps. Apply a second layer of compound if needed, let dry, and re-sand. Retexture this portion of the wall, if required. Aerosol cans of texture work well. Now you can paint over the repairs.

Larger random cracks and those exposed at seams require a little more time. Use mesh tape for angling cracks and paper tape designed specifically for sheetrock to use on seams, along with compound and the putty knife.

Clean the area around the crack. Remove all old tape, texturing, or stucco. If the crack is at a seam and nails have begun to pop, you will want to remove old nails and add new ones. Do not sink the nails as that will damage the sheetrock further.

Use the putty knife and make several swipes to press the compound deeply into the crack. Allow to dry. Take the mesh or paper tape and center over the crack. Cover with a thin layer of compound and smooth out. Allow to dry and begin sanding until the area is free of ridges and bumps. With mesh tape, you may need to apply a second layer of compound, let dry, and then sand.

Keep layering, drying, and sanding until you have a smooth repair. Keeping the area flush with the rest of the wall may be difficult. One remedy is to feather out the compound gradually to the surrounding area to hide the slight rise.

If you notice any defects after the compound has dried, keep sanding and re-compounding until the area is smooth.

Remember that drying times vary based on type of compound used along with temperature and humidity.